The treatment of pain conditions is of great importance in medicine. There is currently a world-wide need for additional pain therapy. The pressing requirement for a specific treatment of pain conditions or as well a treatment of specific pain conditions which is right for the patient, which is to be understood as the successful and satisfactory treatment of pain for the patients, is documented in the large number of scientific works which have recently and over the years appeared in the field of applied analgesics or on basic research on nociception.
PAIN is defined by the International Association for the Study of Pain (IASP) as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage (IASP, Classification of chronic pain, 2nd Edition, IASP Press (2002), 210). Even though pain is always subjective its causes or syndromes can be classified. Especially neuropathic pain which in the past years has developed into a major health problem in broad areas of the population needs a very specific treatment, especially considering that any treatment of neuropathic pain is extremely sensitive to the causes behind the pain, be it the agent/disease ultimately causing it or the mechanistic pathway over which it develops. So, in a majority of cases a substance being able to treat one subtype of neuropathic pain is not—or is at least not necessarily—able to treat other specific subtypes due to the highly diverse nature of this generalized symptom called neuropathic pain.
On the other hand cancer and the therapy thereof are one of the biggest health concerns in the world. Besides surgery and close to always supplementing it chemotherapy is the method of choice for controlling or helping patients struck by carcinomas.
Chemotherapy is the use of chemical substances to treat disease and in the sense of this invention refers primarily to the use of cytotoxic drugs (called chemotherapeutic drugs) to treat cancer. Chemotherapy in cancer consists of a personalized combination of potent chemotherapy drugs, designed to slow rapid cancer tumor growth, shrink tumors, kill cancer cells, and prevent the spread of cancer. The chemotherapeutic drugs prevent cells from replicating in the typical, out-of-control manner in which cancer cells divide.
Peripheral neurotoxicity is a clinically significant complication or cancer chemotherapy. For several of the most effective drugs (e.g. taxanes, vincristine, cisplatin), neurotoxicity is dose-limiting and sometimes forces the termination of otherwise successful therapy (Polomano and Bennett, 2001). Since these drugs are the treatment of choice for a multitude of lymphoid end solid tumours, hundred of thousands of patients each year are affected. Sensory abnormalities from antineoplastic-evoked neurotoxicity range from mild paresthesiae or dysesthesiae in many patients to a chronic painful peripheral neuropathy in a subset (Quasthoff and Hartung, 2002). The occurrence and severity of the neuropathy is dependent on single dose intensity, duration of treatment, cumulative dose, prior or concurrent treatment with other neuropathic drugs and co-existing conditions such as diabetes and alcohol abuse (Alberts et al., 1995; Postma et al., 1995; Forsyth et al., 1997; Quasthoff and Hartung, 2002). Thus it is known that as a result of Chemotherapy in a considerable number of cases neuropathic pain/allodynia/hyperalgesia develops. This is a very specific, development of symptoms coming from neurotoxicity of the chemotherapeutic drug and treatment of that is crucial for assuring quality of live for patients suffering these consequences of chemotherapy.
Therefore, the objective of the present invention was to provide a new form of treatment for neuropathic pain/allodynia/hyperalgesia developing as a consequence of Chemotherapy.